Add an example how to use Flow CDI with Vaadin App Layout

[mrts]

According to official Vaadin documentation, the Vaadin Bakery App Starter showcases "the best practices for all layers when building a business grade web application with Vaadin". Bakery App Starter uses Vaadin App Layout in the main view.

However, Bakery App Starter is available only for Spring, so it would be nice to have a similar example for CDI as well.